This invention relates to a thermostat, and more particularly to a thermostat used in combination with a clock.
With the increasing and spiralling costs of fuel and this nations's committment to conservation, greater attention has been focused on the principal regulatory mechanism found in most homes for heating and cooling, the thermostat. Thermostats are temperature sensitive units which generally operate a remotely located relay by providing control signals over a pair of wires to close or open the relay as appropriate. By the opening or closing of a relay, an appropriate heating or cooling mechanism is actuated to alter the ambient temperature in the environment of the thermostat, thus providing the user with a desired temperature level.
Some thermostats also have clocks provided thereon for displaying the time of day. As described above, there are generally a pair of wires between a thermostat and the remotely operated relay, and this pair of wires carries the control signals between the thermostat and relay. When clocks are added to the thermostat, an additional third wire is required to provide power to the clock. As can be appreciated, such a third wire complicates the installation, is more expensive, and generally limits the installation to only those having expertise in the thermostat field. Some attempts have been made to eliminate the need of a third wire, and these attempts have included the use of a battery located within the thermostat-clock unit to provide power for the clock. Clearly, such an approach has its limitations, since batteries need replacement, are expensive, and when considered in light of the lifetime of the thermostat, can become much more expensive than the thermostat itself.
Thermostats generally display only limited information, such as the temperature and time of day. Frequently, the user does not know whether or not the heating or cooling unit is operated, and often when it is desired to heat a room, the user will move the desired thermostat setting much higher than appropriate because the user may be unaware that the heating unit is operating. In some units, the heating unit is operated after a delay time, so that this over setting of the desired temperature is inappropriate and causes unnecessary and wasteful consumption of fuel.
Some thermostats have the abilities to have separate day and nighttime desired temperatures set, and these are automatically operated as the appropriate times are reached. In some cases, the user may want to temporarily change the time of switching from day to nighttime control, and this can only be done by altering the daytime setting. Thus, if the user were leaving home for the night at 4:00 p.m., it would be undesirable for the ambient temperature to be maintained at a daytime level. Consequently, for that one night, it would be preferable to change the time of actuating the nighttime control to 4:00 p.m. rather than that which had previously been set. With currently available controls, this can only be done by reducing the daytime control at 4:00 p.m., which setting is then maintained fixed until changed. As a consequence, in many cases, the user forgets to alter the daytime level before leaving, or alter it after returning so that inappropriate and wasteful usage of the heating or cooling mechanism may occur.
An object of this invention is to provide an integrated thermostat-clock unit which may be installed by the home owner using only the conventional two wires employed.
Another object of this invention is to provide such a combined thermostat-clock unit which is more efficient regarding the use of energy.
Yet another object of this invention is to provide such a unit which is dependable, reasonably priced, and easy to install, whether by an expert or by an amateur.
Another object of this invention is to provide a thermostat which is capable of switching from day to nighttime control for a single time period, and automatically revert to the time controls previously set.
Still another object of this invention is to provide such a unit which is capable of displaying the condition of the heating or cooling unit, whether or not said unit has actually yet begun to operate.
Another object of this invention is to provide such an integral unit which is capable of displaying a number of functions such as time, temperature, whether in degrees Fahrenheit or Centigrade, nighttime setting, daytime setting, and the desired nighttime and daytime temperature levels.
Another object of this invention is to provide such a display which is easy to read, attractive, and is in the digital form.
Other objects, features and advantages of this invention will become more apparent from the following description.